KD sand tee molds are made from thin aluminum. They are sometimes found dented or dinged up because thin aluminum is not the strongest material. This example, however, is in pristine condition, with the spring loaded plunger still in perfect working order. After loading up the mold with wet sand, just place the mold on or just above the ground and push down on the top of the tee. The plunger will move down, dislodging the newly formed sand tee onto the ground. Then place the ball in the small depression left in the top of the sand by the slightly convex plunger.
The top of this plunger on this mold is marked "K-D Mfg Co, Lancaster, PA" and the bottom of the plunger is marked "Pat 2.8.27" This patent date references the US Patent (No. 1,616,908) issued on February 8, 1927, to Harry W. Kulp, the inventor of this particular sand tee.